November 24, 2024, 01:53:10 PM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: Short Half Life but Still Around...  (Read 13538 times)

0 Members and 1 Guest are viewing this topic.

kct

  • Guest
Short Half Life but Still Around...
« on: July 29, 2005, 06:00:46 PM »
I just took an exam and I'm dying to know the answer to this question:

Pb-238(I think this was the mass number but i'm not 100& sure), has a half life of 23.8 days. Yet, it occurs naturally and we can still find traces of it today. Why?

I thought it was because it is the product of radiocative elements decaying.. Could this be possible?
Logged

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27861
  • Mole Snacks: +1813/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re:Short Half Life but Still Around...
« Reply #1 on: July 29, 2005, 06:18:40 PM »
Quote from: kct on July 29, 2005, 06:00:46 PM
I thought it was because it is the product of radiocative elements decaying.. Could this be possible?

Possible, although decay is not the only possible source of radioactive isotopes. Think C-14 for example. Think about all atoms being in the vicinity of radioactive one.
Logged
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline Grejak

  • Chemist
  • Regular Member
  • *
  • Posts: 43
  • Mole Snacks: +5/-0
  • Gender: Female
Re:Short Half Life but Still Around...
« Reply #2 on: July 29, 2005, 10:06:59 PM »
Quote from: kct on July 29, 2005, 06:00:46 PM
I thought it was because it is the product of radiocative elements decaying.. Could this be possible?

Yeah, that is one of the possible reasons, especially for heavier isotopes such as 226Ra.  Another possible reason is cosmic ray interactions in the upper atmosphere.  About 99% of cosmic rays are hydrogen or helium, but the other 1% cover the range of the periodic table.  When these rays collide with the atmosphere they can cause nuclear reactions, leading the radioactive isotopes.
Logged

Offline jdurg

  • Banninator
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 1366
  • Mole Snacks: +106/-23
  • Gender: Male
  • I am NOT a freak.
Re:Short Half Life but Still Around...
« Reply #3 on: July 30, 2005, 07:39:51 PM »
The more likely, and probably correct, answer in this case is the decay of other radioisotopes.  Because there are other elements with isotopes that have half-lives much longer than 23.8 days, it's highly probable that at least one decay chain has that particular isotope of lead in it.
Logged
"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists

Offline Mitch

  • General Chemist
  • Administrator
  • Sr. Member
  • *
  • Posts: 5298
  • Mole Snacks: +376/-3
  • Gender: Male
  • "I bring you peace." -Mr. Burns
    • Chemistry Blog
Re:Short Half Life but Still Around...
« Reply #4 on: July 31, 2005, 01:26:50 AM »
There is no such thing at Pb-238. ;)
Logged
Most Common Suggestions I Make on the Forums.
1. Start by writing a balanced chemical equation.
2. Don't confuse thermodynamic stability with chemical reactivity.
3. Forum Supports LaTex
Pages: [1]   Go Up
« previous next »
Sponsored Links